The invention falls within the field of chassis for motor vehicles, notably electrically powered or hybrid vehicles. In order to ensure that electrically powered or hybrid vehicles have sufficient range, accumulator batteries have to be carried on board. The volume of these batteries is substantially greater than the volume occupied by a conventional energy reserve, for example a fuel tank.
One solution is to make use of a volume delimited under the passenger seat, by modifying the profile of the floor so as to isolate this volume from the passenger compartment. The passenger seat then rests directly on a raised region of the floor. The height of the seat may be the same as the height of the seat in vehicles of the same range built to be powered by a combustion engine, or may be higher.
Patent application JP 07 156 826 thus describes a chassis structure for an electrically powered motor vehicle, in which structure a volume under the front and rear passenger seats is set aside for the battery by separating this volume from the passenger compartment. Vertical raiser plates are positioned at the front and at the rear of the seats. A raised floor seating region extends from the front backward between these vertical raiser plates and extends laterally between lateral raiser supports which are fixed to the lateral flanks of the bodywork.
Such a structure cannot be applied to a three-door vehicle because the rear passenger seats need to be flanked by fixed bodywork flanks, to which the lateral raiser supports are assembled. Further, where there is a desire to offer the same vehicle in an electrically powered version and in a combustion-engine powered version, the line of spot welds used for assembling the floor elements to the chassis frame side members of the vehicle may not follow the same geometry for the electric vehicle as for the combustion engine vehicle. This then forces the need, in order to produce the two vehicles to install two separate welding lines, thus increasing both development and production costs.